

        window.alert = function (msg) {
            var maskBg = '#0000002b';						//蒙版展示色
            var zIndex = 999999;							//修改弹出层z-index,应为最顶层,避免被覆盖
            var desColor = '#1f0000'						//提示信息字体颜色
            var buttonVal = '确定';							//确定按钮名称
            var btnBgColor = '#f61717';						//确定按钮背景颜色
            var btnColor = '#fff';							//确定按钮字体颜色
            var btnAlign = 'right';							//按钮在水平位置,默认居中,变量值:left,center,right
            var style = `
    			<style class="mask-style">
    				.box-sizing{
    					box-sizing: border-box;
    				}
    				.alertMask{
    					position: fixed;	/*生成绝对定位的元素，相对于浏览器窗口进行定位*/
    					display: flex;
    					display: webkit-flex;
    					flex-direction: row;
    					align-items: center;
    					justify-content: center;
    					width: 100%;
    					height: 100%;
    					top: 0;
    					left: 0;
    					z-index: `+ zIndex + `;
    					background: `+ maskBg + `;
    				}
    				.alertContainer{
    					min-width: 240px;	/*容器最小240px*/
    					max-width: 320px;	/*容器最大320px*/
    					background:#fff;
    					border: 1px solid `+ maskBg + `;
    					border-radius: 3px;
    					color: `+ desColor + `;
    					overflow: hidden;									
    				}
    				.alertDes{
    					padding: 35px 30px;
    					text-align: center;
    					letter-spacing: 1px;
    					font-size: 14px;
    					color: `+ desColor + `;
    				}
    				.alertDes img{
    					max-width: 100%;
    					height: auto;
    				}
    				.alertConfirmParent{
    					width: 100%;
    					padding: 20px 30px;
    					text-align: `+ btnAlign + `;
    					box-sizing: border-box;
    					background: #f2f2f2;
    				}
    				.alertConfirmBtn{
    					cursor: pointer;
    					padding: 8px 10px;
    					border: none;
    					border-radius: 2px;
    					color: `+ btnColor + `;
    					background-color: `+ btnBgColor + `;
    					box-shadow: 0 0 2px `+ btnBgColor + `;
    				}
    			</style>
    		`;

            var head = document.getElementsByTagName('head')[0];
            head.innerHTML += style		//头部加入样式,注意不可使用document.write()写入文件,否则出错

            const body = document.getElementsByTagName('body')[0];

            var alertMask = document.createElement('div');
            var alertContainer = document.createElement('div');
            var alertDes = document.createElement('div');
            var alertConfirmParent = document.createElement('div');
            var alertConfirmBtn = document.createElement('button');

            body.append(alertMask);
            alertMask.classList.add('alertMask');
            alertMask.classList.add('box-sizing');

            alertMask.append(alertContainer);
            alertContainer.classList.add('alertContainer');
            alertContainer.classList.add('box-sizing');

            alertContainer.append(alertDes);
            alertDes.classList.add('alertDes');
            alertDes.classList.add('box-sizing');

            alertContainer.append(alertConfirmParent);
            alertConfirmParent.classList.add('alertConfirmParent');
            alertConfirmParent.classList.add('box-sizing');

            alertConfirmParent.append(alertConfirmBtn);
            alertConfirmBtn.classList.add('alertConfirmBtn');
            alertConfirmBtn.classList.add('box-sizing');
            alertConfirmBtn.innerText = buttonVal;

            //加载提示信息	
            alertDes.innerHTML = msg;
            //关闭当前alert弹窗
            function alertBtnClick() {
                body.removeChild(alertMask);
                maskStyle = head.getElementsByClassName('mask-style')[0];
                head.removeChild(maskStyle);	//移除生成的css样式

            }
            alertConfirmBtn.addEventListener("click", alertBtnClick);
        }

        
